Cancer is the loss of control of one or more of the regulatory systems which regulate the growth of cells and tissues. An uncontrolled growth of a particular tissue or cell type is a specific type of cancer. There are many types of cancer. In the treatment of cancer, one or more therapeutic remedies are typically used in attempts to cure the disease or ameliorate its effects. Many differences exist between classes of tumors and, indeed, individual tumors of the same type. There are many possible therapies for cancers in general. Nonetheless, most therapies do not work, or do not work to the extent necessary to provide the degree of cure, remediation or desired palliative effect for a specific cancer. Because of this, it is sometimes difficult, time-consuming and expensive to attempt to determine what therapeutic compounds may be effective to treat a particular tumor or cancer type. Oncologists and other physicians therefore often choose a therapy based on little or no pragmatic information regarding the specific tumor. In effect, their determinations of which therapy or therapies to employ arc often guesses. It is therefore very important to be able to more effectively match a specific effective therapy to a specific tumor, and to be able to do so in a reasonable amount of time. As a consequence of these needs, many technologies have attempted to address these needs, but none have been acceptably successful.
Various experiments have been directed toward measuring the effects of certain therapies on malignant cells in vitro. One of these attempts is shown in “Effects of Radiation on a Three-Dimensional Model of Malignant Glioma Invasion” International Journal of Devl. Neuroscience, Vol. 17, issue 5-6, 643-651, August 1999, (Bauman et al.). The Bauman et al. researchers used suspensions of an established cell line, the C6 astrocytoma line, to show that the three-dimensional migration of known, cultured malignant cells into a collagen matrix could be observed. The malignant glioma cells thus cultured, disrupted and processed into cloned spheroids, which were then implanted into a gel matrix, and then subjected to one or more doses of fractionated radiation. Changes in the distance of invasion in response to single dose and fractionated radiation were measured over a period of 5 days.
Similar experiments were reported in “Effects Of Radiation On A Model Of Malignant Glioma Invasion”, Journal of Neuro-Oncology 44: 223-231, 1999, (Baumann et al.). In this reference, the Baumann et al. researchers used the same C6 cell line and experiment-al protocols to test BCNU and dexamethasone, and to compare these results with those of radiation dosing on the transformed cells.
Significantly, in both series of experiments reported by Bauman et al., the cloned C6 astrocytoma cells were subjected to disruption by trypsinization, and also subjected to centrifugal forces for 3-4 weeks in spinner flasks. Thus, the cells of Bauman et al were already known to be transformed to a great extent, were generations removed from the original tissue, required disruptive chemical processing, and were a subset of cloned malignant cells at the time they were subject to radiation doses. C6 astrocytoma cells were maintained in tissue culture as cloned representatives of malignant rat glioma cells. Indeed, the cells of the Bauman et al. experiments were removed and established as a cell line years before they were subjected to the experiments of Bauman et al.
In significant contrast, the present invention uses a sample quantity of fresh tissue taken directly from an animal, such as a human patient. Significantly, the samples used in the present invention are not disrupted by trypsin or other enzymes, but are mechanically divided into sample portions of appropriate sizes for testing. Thus, the present methods maintain the cell-to-cell contact of the sample tissue as if it were still in vivo. An additional difference pertains to the fact that the experiments of Bauman et al. used an established cell line, that is, cells that were already known to have been transformed long before, and in an unknown way, to an extent great enough that they could be used to establish a tissue culture cell line. One could not therefore expect the cells of Baumann et al. to behave in a manner reasonably replicative of fresh or in vivo cells.
Others have attempted to provide ways of evaluating the response of tumor cells to chemotherapeutics. In U.S. Pat. No. 5,242,806 to Yen-Maguire et al., entitled Method For Conducting The Cytotoxicity Assays On Tumor Cells, a “growth matrix” of bovine cornea endothelium cells is sometimes employed as a coating in the wells of multi-well plates in order to facilitate the attachment of cells to the plate surfaces. Essentially, Yen-McGuire discloses ways of culturing cellular suspensions which have been grown in two dimensions, and then assaying the responses of the processed cells to various cytotoxic or chemotherapeutic compounds.
The cellular suspensions of Yen McGuire are provided with a defined, selective growth medium which is designed and formulated to promote the growth of epithelial tumor cells while inhibiting the growth of normal cells. Yen-McGuire thus teaches the use of selective nutrition to skew cellular growth and behavior. Indeed, the relative amount of cellular growth is measured to provide information regarding the sensitivity of the highly processed tumor cells. Thus, Yen-McGuire does not provide any analysis with respect to an original tumor sample or fragment thereof, nor does it comprehend the advantages of an in vitro system which replicates significant aspects of the three-dimensional environment of tumor tissue in vivo.
These problems regarding the lack of analytic tools which are effectively usable to provide information specific to particular tumors, combined with the fact that cancer often progresses rapidly, have created a significant need for means and methods to quickly obtain information useful for testing and evaluating specific therapies, for example, therapeutic compounds, to determine their effectiveness with respect to particular tumors or cancer types. There is thus a significant need for such means and methods.